Macronutrients—Phosphorus and Potassium

1999 ◽  
Author(s):  
Robert F. Keefer
Keyword(s):  
N Fertilization ◽  
Major Constituent ◽  
Seed Formation ◽  
Phosphorus Toxicity ◽  
Greenhouse Culture ◽  
Energy Relationships ◽  
Purple Coloration ◽  
High Concentrations ◽  
Phosphorus And Potassium ◽  
Fibrous Roots

Plants have a P concentration between 0.03 and 0.70%, but the usual amount is between 0.1 and 0.4%. Phosphorus is found in every living cell of a plant and is involved in genetic transfer and energy relationships. The actively growing parts, that is, stem tips, new leaves, and new roots, need much P. Seeds, especially at maturity, also have a rich supply of P acting as reserve food. Phosphorus is used in plants for (a) root development—especially the lateral and fibrous roots; (b) cell division—energy for metabolism; (c) reproduction—flowering, fruiting, seed formation all controlled by nucleic acids; (d) maturation—counteracts the ill effects of excessive N fertilization; arid (e) disease resistance— especially important in root rots of seedlings. Plant P is a major constituent of chromosomes present as DNA (deoxyribonucleic acid) used in reproduction and RNA (ribonucleic acid) used in growth processes. Plant P is also a constituent of adenosine triphosphate (ATP) that stores energy for plant use, along with many other phosphate compounds, such as phytin (inositol hexaphosphate) stored in seeds, phospholipids in the chloroplasts, and complexes of sugars, sugar amines, aldehydes, amides, and acids—all involved in plant metabolism. Deficiency of P is not striking or characteristic and is difficult to diagnose. The older leaves may be dark bluish-green, bronze, or purple. The stalks are thin, leaves small, limited lateral growth, delayed maturity, and defoliate prematurely. Probably the most obvious symptom would be the purple coloration, but this is exhibited by only a limited number of plants. The best way to determine if a plant is deficient in P would be to conduct a plant tissue test. If the P level is lower than 0.2% P, then P probably is deficient and the soil in which the plant is growing would benefit from P fertilization. . . . Phosphorus Toxicity? . . . Phosphorus toxicity has not been observed in the field and has only been evident in greenhouse culture solutions when P was present at extremely high concentrations.

A study of the phosphorus responses of a wide range of accessions from the genus Stylosanthes

1974 ◽  
Vol 25 (6) ◽  
pp. 847 ◽  
Author(s):  
RK Jones
Keyword(s):  
Growth Rates ◽  
Dry Matter ◽  
Phosphorus Uptake ◽  
Numerical Classification ◽  
Foliar Symptoms ◽  
Severe Deficiency ◽  
Wide Range ◽  
Phosphorus Toxicity ◽  
High Concentrations ◽  
Phosphorus Levels

The effects of a wide range of phosphorus levels on the growth and uptake of phosphorus by 30 accessions of the legume genus Stylosanthes, representing seven species, were compared in a glasshouse experiment. The basic data from the experiment were subjected to a numerical classification, and accessions with similar patterns of response were grouped to simplify description and interpretation of the results. Differences in growth and phosphorus uptake under conditions of severe deficiency were fairly small, but there were appreciable differences between groups in the dry matter produced per unit phosphorus absorbed. With progressive improvement in the supply of phosphorus, large differences developed between the groups in growth and phosphorus uptake. One group, in which nodulation was partially or completely ineffective, responded poorly in growth and phosphorus uptake to additions of phosphorus. Other groups, however, were effectively nodulated, and appeared to differ considerably in their inherent growth rates and hence in their uptake of phosphorus during the 55 days of the experiment. At moderately high levels of applied phosphorus (equivalent to between 96 and 192 kg P/ha) accessions in several groups developed foliar symptoms resembling 'phosphorus toxicity', had depressed yields of dry matter, and accumulated phosphorus in their tops to high concentrations.

scholarly journals Effects of Graphene on Larix olgensis Seedlings and Soil Properties of Haplic Cambisols in Northeast China

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 258 ◽  
Author(s):  
Jinfeng Song ◽  
Kai Cao ◽  
Chengwei Duan ◽  
Na Luo ◽  
Xiaoyang Cui
Keyword(s):  
Northeast China ◽  
Chemical Properties ◽  
Average Diameter ◽  
Available Phosphorus ◽  
Larix Olgensis ◽  
Nitrogen And Phosphorus ◽  
Low Concentrations ◽  
Physiological Indexes ◽  
High Concentrations ◽  
Phosphorus And Potassium

We investigated the impacts of graphene application at different concentrations on the growth and physiological characteristics of Changbai larch (Larix olgensis A. Henry) seedlings and the chemical properties and enzyme activities of Haplic Cambisols under these seedlings. The aim is to evaluate the environmental effects of graphene on the afforestation species and the zonal forest soils of Northeast China. Seedlings receiving 0 (CK), 25, 50, 100, 250, or 500 mg L−1 graphene were incubated for 30, 40, or 50 days. Low concentrations (25–50 mg L−1) of graphene increased the dry masses of root, stem, and leaf; however, high concentrations (100–500 mg L−1) inhibited them. Compared with those under 0 mg L−1 graphene, the root length, surface area, volume, and average diameter all increased during the early stages of incubation (i.e., 30 and 40 days) under low concentration of graphene (<50 or 100 mg L−1) and decreased at higher graphene concentration (>100 mg L−1); at 50 days, they were significantly inhibited. At 30 days, graphene decreased superoxide dismutase (SOD) and peroxidase (POD) activities, as well as pigment, soluble protein, and proline contents, and the decline increased with increasing graphene concentration; at 40 and 50 days, the above parameters increased initially and then decreased, reaching a maximum at 50 mg L−1. The changes in relative conductivity and malondialdehyde (MDA), superoxide anion and hydrogen peroxide contents were the opposite of those in the physiological indexes mentioned above. Therefore, graphene caused different degrees of oxidative stress in L. olgensis seedlings. At 30 days, graphene generally increased the organic matter, hydrolytic nitrogen, and available phosphorus and potassium contents of Haplic Cambisols, but these parameters decreased at 40 and 50 days. Graphene generally decreased acid phosphatase, urease, dehydrogenase, and catalase activities. Therefore, when graphene reaches a certain content level in this soil, it may also affect nitrogen and phosphorus cycling.

1. Soils and crops

2016 ◽  
pp. 4-31
Author(s):  
Paul Brassley ◽  
Richard Soffe
Keyword(s):  
Major Constituent ◽  
Cultivation Systems ◽  
Phosphorus And Potassium ◽  
Constituent Elements ◽  
Nitrogen Phosphorus

‘Soils and crops’ looks at what soils are, how they differ, how they are classified, and how farmers manage them. Soil anchors and feeds the crops and the type and depth of it is fundamental to the crops that can be grown. Plants get their major constituent elements—carbon, hydrogen, and oxygen—from the air they take in through their leaves and the water taken up by their roots. They also require several other nutrients, the most important being nitrogen, phosphorus, and potassium. How do plants grow? What prevents them from growing? How can we improve their growth? These questions are considered along with some of the major crops and cultivation systems used.

scholarly journals La fertilidad del suelo afecta el crecimiento, nutrición y rendimiento de algodón cultivado en dos sistemas de riego y diferentes dosis de nitrógeno.

2019 ◽  
Vol 37 (1) ◽  
pp. 7
Author(s):  
Jesús Santillano Cázares ◽  
Luis Guadalupe Roque Díaz ◽  
Fidel Núñez Ramírez ◽  
Raúl Leonel Grijalva Contreras ◽  
Fabián Robles Contreras ◽  
...  
Keyword(s):  
Drip Irrigation ◽  
Cell Extract ◽  
N Fertilization ◽  
Yield Response ◽  
High Fertility ◽  
Agronomic Efficiency ◽  
Cotton Crop ◽  
Use Efficiency ◽  
High Concentrations ◽  
N Rates

Intrinsic soil fertility and the method of irrigation can affect the efficiency of nitrogen (N) fertilization, modify the yield goal, growth, and nutritional status of crops. A study was carried out with the objective of determining yield, growth, water use efficiency (WUE), agronomic efficiency of N (AEN), NO3- concentration in petiole cell extract (PCE) and chlorophyll index (SPAD) in a cotton crop by effect of N rates and two irrigation methods. The study consisted of two experiments established in soils of high fertility [˃13 g kg-1 organic matter (OM) and N-NO3- ˃ 30 mg kg], with varying N fertilization rates: a) flood irrigation (FRR, 11 and 220 kg N ha‑1), and b) drip irrigation (FRG, 11 to 440 kg N ha-1). Plant height and number of nodes were not affected by the applied treatments. SPAD values and NO3- concentrations in PCE were cubically related to crop yield. The highest yield and WUE was obtained in the experiment with drip irrigation. In the FRR experiment no response (P > 0.05) to N fertilization treatments was found. In the FRG experiment, application of 440 kg N ha‑1 reduced yield by 43% compared to the rest of the evaluated rates. AEN was statistically higher (P < 0.001) in treatments fertilized with 11 kg N ha‑1. The low yield response due to application of N in cotton was attributed to high concentrations of N-NO3- and OM that are present in the soils in which the experiments were conducted.

scholarly journals THE ROLE OF WATER IN FLORICULTURAL CROP/INSECT INTERACTIONS

HortScience ◽  
1996 ◽  
Vol 31 (6) ◽  
pp. 917-918
Author(s):  
U.K. Schuch ◽  
J.A. Bethke ◽  
R.A. Redak
Keyword(s):  
Leaf Area ◽  
Cultural Practices ◽  
Insect Pests ◽  
Dry Weight ◽  
N Fertilization ◽  
Cultivar Selection ◽  
High Concentrations ◽  
Insect Interactions ◽  
Fertilizer Regimes

Water stress and N fertilization can have a profound effect on populations of phytophagous insects. While species and cultivar selection can identify plants that are resistant to common insect pests, cultural practices may further decrease the susceptibility to insect attacks. Six poinsettia and six chrysanthemum cultivars were grown under well-watered or water-deficient conditions, and three fertilizer regimes with low, medium, or high concentrations of N. Vegetative plant growth and longevity and fecundity of various insect pests on these plants were determined. Host plant suitability to insects was estimated by the quantity of foliar soluble protein. Low irrigation reduced leaf area and leaf and stem dry weights 36% to 41% in poinsettias and 26% to 28% in chrysanthemum. Leaf area and leaf dry weight increased linearly in response to increasing fertilizer concentrations in poinsettia and chrysanthemum. Cultivar-specific differences were found for all variables of vegetative growth in poinsettiasand chrysanthemum. Cultivar also strongly affected insect preference, development, and fecundity. Low irrigation significantly reduced insect survivorship of the silverleaf whitefly on poinsettias. On chrysanthemum, leafminers, thrips, and melon aphids were unaffected by irrigation or fertilizer treatments. Chrysanthemum cultivar choice strongly affected the number of insects or development time.

scholarly journals Nitrogen, phosphorus, and potassium released by decomposition of palisade grass to soybean in succession

2020 ◽  
Vol 55 ◽  
Author(s):  
Flávia Werner ◽  
André Sampaio Ferreira ◽  
Alvadi Antonio Balbinot Junior ◽  
Adilson de Oliveira Junior ◽  
Julio Cezar Franchini ◽  
...  
Keyword(s):  
Glycine Max ◽  
Nitrogen Fertilization ◽  
N Fertilization ◽  
No Tillage ◽  
K Uptake ◽  
Soybean Crop ◽  
P Release ◽  
Phosphorus And Potassium ◽  
Urochloa Brizantha ◽  
Nitrogen Phosphorus

Abstract: The objective of this work was to determine the nitrogen, phosphorus, and potassium released by N-fertilized Urochloa brizantha straw, desiccated before sowing of no-tillage soybean (Glycine max) in succession. The pasture was grown in three paddocks, each fertilized with one N rate (0, 150, or 300 kg ha-1), and assessed at two desiccation periods (60 or 15 days before soybean sowing), in four replicates. Nitrogen fertilization of U. brizantha pasture increases N and K cycling and the release of these nutrients to the subsequent soybean crop. The quantity of K released by U. brizantha straw fertilized with 150 or 300 kg ha-1 N (about 80 kg ha-1 K) offsets that contained in an export of up to 4 Mg ha-1 soybean grains, assuming zero K losses in the system. An early desiccation of the U. brizantha pasture does not improve K uptake by the soybean crop, since 50% of the nutrient is released in the first 20 days after desiccation. The dynamics of P release from U. brizantha straw (about 6 to 10 kg ha-1 during the soybean crop) is not influenced by N fertilization and the time of pasture desiccation.

The effect of early superphosphate toxicity on the subsequent growth of wheat

1970 ◽  
Vol 21 (6) ◽  
pp. 881 ◽  
Author(s):  
AS Bhatti ◽  
JF Loneragan
Keyword(s):  
Root Growth ◽  
Ammonium Nitrate ◽  
Nutrient Solution ◽  
Moderate Intensity ◽  
Cereal Crops ◽  
Subsequent Growth ◽  
Phosphorus Toxicity ◽  
High Concentrations ◽  
Complete Nutrient Solution

The effects of 19 days' treatment with three rates of superphosphate and four rates of ammonium nitrate application on the growth of wheat in a siliceous sand have been studied both during and after treatment. Severe necrosis of leaf tips developed after 7 days at high superphosphate and no ammonium nitrate. Plant tops with symptoms had high concentrations of phosphorus. Decreasing superphosphate or increasing ammonium nitrate gave lower phosphorus concentrations and fewer symptoms in plant tops. Ammonium nitrate depressed phosphorus concentrations by promoting top growth relative to root growth. Symptoms were ascribed to phosphorus toxicity. When plants with severe symptoms of phosphorus toxicity were transplanted to siliceous sand and watered with complete nutrient solution containing adequate phosphate, tillering was delayed and dry weights of tops, roots, and grains were depressed about 30%. Plants with symptoms of only moderate intensity recovered and grew as well as plants which initially had mild or no symptoms. The results suggest that the intensity of phosphorus toxicity reported to occur in cereal crops in the field is not likely to depress yields seriously.

scholarly journals Quality of Organic Vegetables Grown in Two Certified Sites on the Outskirts of Bucharest Municipality

2017 ◽  
Vol 11 (2) ◽  
pp. 173-185
Author(s):  
Mihaela Lungu ◽  
Sorin Liviu Ștefănescu ◽  
Monica Dumitrașcu
Keyword(s):  
Mineral Composition ◽  
Mineral Nutrition ◽  
Plant Protection ◽  
Mineral Elements ◽  
Nutrition Status ◽  
Yield Quality ◽  
High Concentrations ◽  
Phosphorus And Potassium ◽  
Certified Organic ◽  
The One

Abstract Soil fertility properties, irrigation water quality, mineral nutrition, and some vegetables mineral composition were studied in the frame of a project regarding yield quality monitoring in certified organic vegetable farms, in two farms placed on the outskirts of Bucharest Municipality which provide products for the town’s organic market. Chemical analysis of the soil samples collected from the two farms reflects a good fertility, close to the natural one of this region soils, with well-balanced organic matter, total nitrogen, accessible phosphorus and potassium contents. The nitrates contents concord with the plants nutrition demands and don’t present the risk to accumulate in vegetables or to leach into the groundwater. Slightly increased microelements, both total and soluble forms, occur. Soil microbiological properties are favorable for vegetable plants growth. A good biodiversity is noticed. There are differences between soil properties in open field and greenhouses, induced both by the type and degree of mechanical works and materials applied for fertilization and plant protection. Good conditions are generally created for plants mineral nutrition. Mineral nutrition status of the vegetables grown in organic conditions, assessed by the leaves mineral composition, doesn’t differ from the one of the vegetables grown in conventional conditions. The vegetables (fresh material) harvested from the two studied farms have good, even high, concentrations of mineral elements important for the yield nutritional quality. The excessive microelements quantities noticed in soil don’t transfer in the yield, so the latter quality and nutritional properties are not altered.

scholarly journals THE ROLE OF WATER IN FLORICULTURAL CROP/INSECT INTERACTIONS

HortScience ◽  
1996 ◽  
Vol 31 (6) ◽  
pp. 917F-918
Author(s):  
U.K. Schuch ◽  
J.A. Bethke ◽  
R.A. Redak
Keyword(s):  
Leaf Area ◽  
Cultural Practices ◽  
Insect Pests ◽  
Dry Weight ◽  
N Fertilization ◽  
Cultivar Selection ◽  
High Concentrations ◽  
Insect Interactions ◽  
Fertilizer Regimes

Water stress and N fertilization can have a profound effect on populations of phytophagous insects. While species and cultivar selection can identify plants that are resistant to common insect pests, cultural practices may further decrease the susceptibility to insect attacks. Six poinsettia and six chrysanthemum cultivars were grown under well-watered or water-deficient conditions, and three fertilizer regimes with low, medium, or high concentrations of N. Vegetative plant growth and longevity and fecundity of various insect pests on these plants were determined. Host plant suitability to insects was estimated by the quantity of foliar soluble protein. Low irrigation reduced leaf area and leaf and stem dry weights 36% to 41% in poinsettias and 26% to 28% in chrysanthemum. Leaf area and leaf dry weight increased linearly in response to increasing fertilizer concentrations in poinsettia and chrysanthemum. Cultivar-specific differences were found for all variables of vegetative growth in poinsettiasand chrysanthemum. Cultivar also strongly affected insect preference, development, and fecundity. Low irrigation significantly reduced insect survivorship of the silverleaf whitefly on poinsettias. On chrysanthemum, leafminers, thrips, and melon aphids were unaffected by irrigation or fertilizer treatments. Chrysanthemum cultivar choice strongly affected the number of insects or development time.

Zinc in subterranean clover (Trifolium subterraneum L. cv. Seaton Park). II. Effects of phosphorus supply on the relationship between zinc concentrations in plant parts and yield

1982 ◽  
Vol 33 (6) ◽  
pp. 1001 ◽  
Author(s):  
DJ Reuter ◽  
JF Loneragan ◽  
AD Robson ◽  
D Plaskett
Keyword(s):  
Zinc Deficiency ◽  
Subterranean Clover ◽  
Zinc Content ◽  
Trifolium Subterraneum ◽  
Plant Analysis ◽  
Plant Parts ◽  
Phosphorus Toxicity ◽  
Zinc Concentrations ◽  
High Concentrations ◽  
The Relationship

The effect of phosphorus on the relationship of zinc concentrations in various plant parts to yield of Seaton Park subterranean clover was examined. Plants were grown in a glasshouse at three levels of phosphorus (39, 65 and 130 mg phosphorus/pot; denoted P1, P2 and P3 respectively) and six levels of zinc added in factorial combination to a sand deficient in both phosphorus and zinc. At the lowest three levels of zinc supply, plants were severely to moderately deficient in zinc: in them, increasing levels of phosphorus depressed growth and induced high concentrations of phosphorus (> 1 % DM) in several plant parts and symptoms of phosphorus toxicity in leaves. At the highest three levels of zinc supply, plants at P1 were phosphorus deficient: application of P2 and P3 increased growth and induced zinc deficiency primarily by diluting the available zinc. In addition, P3 appeared to depress slightly the zinc content of plant tops by another mechanism. In severely zinc-deficient plants, phosphorus supply changed the relationships between zinc concentrations in various plant parts and yield of whole tops, probably as the result of phosphorus toxicity. In the youngest open leaf blades, an asymptotic relationship at P1 changed at P2 and P3 to sigmoidal and to 'Piper-Steenbjerg' relationships respectively. These changes would not have invalidated the use of plant analysis for diagnosing zinc deficiency. In moderately zinc-deficient plants, phosphorus supply had little or no effect on the relationships of zinc concentration in plant parts to yield of shoots. As a result, critical concentrations in plant parts generally remained constant over the whole range of phosphorus supply. The data refute suggestions that high levels of phosphorus in plant parts inactivate the zinc within them, thus removing a potential problem in the use of plant analysis for diagnosing zinc deficiency in subterranean clover. The results confirm the previous suggestion that a concentration range of 12-14 �g zinc/g in the youngest, open leaf blade is critical for diagnosis of zinc deficiency in subterranean clover.

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